Voltage sensing device

Abstract

A voltage sensing device with which high-precision voltage sensing is possible without acquiring a unique correction constant for each device. A pair of voltage input nodes NCk and NCk-1 are selected from n+1 voltage input nodes NC0-NCn in switch part 10, and the selected voltage input nodes NCk and NCk-1 are connected to inspection input nodes NA and NB. Here, voltage input nodes NCk and NCk-1 and inspection input nodes NA and NB are connected in two types of patterns of different polarity (forward connection, reverse connection) under the control of control part 50, and digital data S30 for the two sensed voltage signals S20 generated in the two types of connection patterns is input to sensed data processing part 40. With sensed data processing part 40, sensed voltage data S40 that represents the potential difference between voltage input nodes NCk and NCk-1 is generated according to the difference in the two sensed voltage signals S20.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This patent application claims priority from Japanese Patent Application No. 2008-226501, filed 3 Sep. 2008, the entirety of which is incorporated herein by reference.TECHNICAL FIELD[0002]The present invention pertains to a voltage sensing device that senses the voltage applied between nodes that are at different electrical potentials relative to a reference potential; more specifically, it relates to a voltage sensing device that senses the voltage of each cell of a secondary battery that has a plurality of cells that are connected in series, for example.BACKGROUND OF THE INVENTION[0003]When a battery supplies energy to the drive system of a hybrid automobile or the like, generally, a voltage of around several hundred V is required; such batteries are often configured by connecting many secondary cells, such as lithium ion batteries, in series. When many secondary cells are connected in series, voltage variations occur because the charac...

AI Technical Summary

Benefits of technology

[0012]In this aspect of the invention, the aforementioned first sensed signals generated by the aforementioned first sensed signal generating part include a fixed error, which is not dependent on the voltage at the aforementioned pair of sense input nodes, due to the effect of the input offset voltage etc. Th...

Problems solved by technology

During charging, for example, the voltage of some cells may be too high and cause problems, such as damage or fire.

However, this makes pre-shipment inspection time-consuming, and there is also the problem that the same operation is required when a device is to be replaced after shipment.

There is also the problem that increased errors due to temporal changes are unavoidable, since the same constant that was acquired at the time of shipment continues to be used.

That is, there is the problem that a great amount of time is required until the voltage values are ascertained.

When the cell module voltage is monitored to judge abnormalities, such as overvoltages, there is the possibility that such a time delay will become a problem from the standpoint of safety.

There is also the problem of increased circuit area and power consumption, since a microcomputer is used.

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